My question is: is this software available for Linux? I have Windows and am not strictly a Linux user. Will Marantz software ever be open source?
No, this application is not compatible with the Linux operating system. I've downloaded the installation package from the official website and the file ended in EXE after extraction which means it will run only on Windows. If you have Linux, install Wine and then you might have a chance running it in Linux while being a Windows app as well.
Download Wine: https://www.winehq.org/
Download product: http://us.marantz.com/us/Products/Pages/ProductDetails.aspx?Catid=RemoteControls&SubCatId=0&ProductId=RC9001